FREETOWN, Sierra Leone — At this time of year, 12-year-old Joseph Sheriff should be sitting in a classroom with other students in this capital city. Instead, he's at home, frantically scribbling notes and listening intently to his family's small radio.

With Sierra Leone on lockdown as the deadly Ebola virus continues to spread throughout West Africa, authorities here are keeping schools shuttered, forcing Joseph and 1.7 million children like him to stay home.